Welcome in H.C.M.
I have gone through your query regarding breathlessness and feeling of lump in throat. As you said you are taking omeprazole
daily for last 2 years, recently you have developed infection in stomach and doctor had given you antibiotics . Your problem arise after taking antibiotics.
Your clinical history favors for-
1- GERD (gastro esophageal reflex disease).
2- Local lesion in larynx
3- Associated chest problem as allergic bronchitis
Here we are excluding GERD as you are already taking omeprazole. thus rest two possibilities are there which may be rule out by thorough examination and necessary investigations.